title: First-principles investigation of the relation between structural and NMR parameters in vitreous GeO2.
abstract: NMR parameters of (73)Ge and (17)O in vitreous GeO(2) and quartz GeO(2), including the isotropic shifts, the quadrupole coupling constants C(Q), and the electric-field-gradient asymmetry parameters η, are determined through density functional calculations. Clear correlations are established between (73)Ge shifts and the mean of the four neighboring Ge-O-Ge bond angles, and between C(Q) and η parameters of (17)O and the local Ge-O-Ge angle. Available experimental data for C(Q) and the corresponding established correlation are used to extract the value of 135° for the average Ge-O-Ge angle in vitreous GeO(2). The features of the Ge-O-Ge bond angle distribution of vitreous GeO(2) derived in this work are consistent with those inferred from other experimental probes.
authors.affiliation: TCM Group, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK. mk531@cam.ac.uk
authors.forename: Mikhail
authors.initials: M
authors.lastname: Kibalchenko
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Yates
authors.forename: Alfredo
authors.initials: A
authors.lastname: Pasquarello